1. Field of the Invention
The present invention relates to elastomeric bushings. In particular, the present invention relates to elastomeric bushings used in motor vehicle suspension systems.
2. Description of the Related Art
Conventional motor vehicle suspension systems often include one or more stabilizer bars to control the degree of roll of the motor vehicle when it negotiates a curve. A typical stabilizer bar is generally C-shaped, having a relatively long intermediate portion disposed laterally with respect to the motor vehicle and a pair of relatively short end portions extending either forwardly or rearwardly to connect a corresponding pair of wheel hubs. The intermediate portion normally is connected to the underside of the vehicle body by a bracket.
The mounting bracket for the intermediate portion of the stabilizer bar typically includes an elastomeric bushing, sometimes termed an insulator, that contacts and supports the stabilizer bar. In most applications it is desirable to use a bushing that permits the stabilizer bar to rotate freely about the axis of the intermediate portion as the wheel hubs travel vertically relative to the vehicle body. Where free rotation is desirable, it is important to minimize friction between the stabilizer bar and the bushing to reduce noise and wear.
Previous efforts to minimize friction at the bushing-stabilizer bar interface have employed low-friction materials as liners covering the bore of the bushing and/or have added lubricants between the bushing and stabilizer bar. Commonly used materials for bushing liners are polyester and polytetrafluoroethylene. Silicone-based grease often is used as a lubricant.
Although conventional stabilizer bar mounting schemes usually are adequate when a motor vehicle is new, performance can deteriorate quickly after exposure to normal road conditions. A particular problem with conventional systems is that dirt, road salt, and other contaminants become lodged between the bushing and the intermediate portion of the stabilizer bar, creating an audible noise when the bar rotates. Many drivers find this noise objectionable.
The present invention is intended to provide an elastomeric suspension bushing that will not produce objectionable noise, even after exposed to dirt, road salt, and other contaminants.
The present invention also is intended to provide a method of manufacturing a noise-suppressing suspension bushing.
Additional advantages of the present invention will be set forth in part in the description that follows, and in part will be obvious from that description or can be learned by practice of the invention. The advantages of the invention can be realized and obtained by the apparatus particularly pointed out in the appended claims.